Process of coating certain materials, such as the surface of paper, is old in the art. The micropackaging technique is a process applying a thin polymeric coating on the surface of materials with the content being the desired fragrance.
It is known that perfume makers introduced perfume into printing ink for readers to sniff such as perfumed advertisements.
Microencapsulation is a well known micro-packaging technique which involves deposition of thin polymeric coatings to minute particles of solids, droplets of liquids, or dispersions of solids in liquids. Such capsules have been used in the pharmaceutical industry and industrial chemicals.
There are several processes for coating minute particles employing the principles and phenomenon of coacervation. This is a generalized phase separation phenomenon involving the emergence from a homogenous solution of polymeric material liquid droplets of concentrated solution rather than solid aggregates. Such separated emergent phase in the form of amorphous, liquid drops, constitutes the coacervate. Deposition of this coacervate around individual minute insoluble particles dispersed in the equilibrium liquid form embroyonic capsules, and appropriate gelling of the coacervate deposits results in useful microcapsules, with or without after-treatment to modify the properties of the containing polymeric wall.
Such processes are described in U.S. Pat. No. 3,137,631 to Soloway which also discloses a fibrous tissue or paper containing such capsules. Additional processes are described in U.S. Pat. No. 4,087,376 and U.S. Pat. No. 4,100,103 to Foris, et al.
U.S. Pat. No. 3,145,184 to Brain teaches a method of entraining microcapsules in fabric by mixing them with laundry detergents and then washing the fabric which does not insure uniform and firm impregnation of the fabric.
U.S. Pat. No. 3,640,629 to Geiser discloses a tape or narrow strip of sheet material having rupturable microcapsules entrapped on its surface.
U.S. Pat. No. 4,201,822 to Cowsar teaches a fabric in which a resin finish is used on the fabric to contain decontamination agents for reaction with toxic substances. No novel method of impregnation is disclosed.